For sometime the front brake pads were holding on to the disc. The brake pistons were not retracting. This affected riding and turning since the brakes were always ON for the front wheel.

Took out the brake pistons. Its cylinder walls had hard crud (looked like rust) accumulated over the years due to perhaps snow and salt and other debris. The pistons had white crust on surface too. All this prevented free movement of one (top) piston.

Each cylinder has 2 seals - a larger piston seal and a smaller dust seal.